Pain, Chemical Transmitter Concepts

Abstract

The word pain covers phenomena ranging from the acute sensation leading to a nocifensive response to long-term or chronic suffering, a disease state. When cross-species comparisons are made, the general evolutionary level of the species involved must be considered. Since pain is such a loose term, better definitions are needed. These may include descriptions of the chemical substrates and neuronal transmitters involved in pain and pain modulation, which are likely targets for intervention by pharmacotherapy.